Internal-combustion engine



June 7, 1927. 1,631,705

E. soKAL INTERNAL COMBUSTION ENGINE Original Filed July 9. 1925 INVENTOR. M Knew BY @7 7 51 TTORNEYS.

Patented June 7, 1927.

UNITED STATES PATENT OFFICE.

EDWARD SOKAL, OF NEW YORK, N. Y., ASSIGNOR TO AMERICAN KATALITE COB- IPOBATION, OF BROOKLYN, NEW YORK, A CORPORATION OF DELAWARE.

INTERNAL-COMBUSTION ENGINE.

Original application filed July 9, 1925, Serial No. 42,583, and in Canada July 6, 1925. Divided and this application filed December 18, 1928. Serial No. 155,587.

This invention relates to internal combustion engines, and more particularly to engines of the relatively high compression y t It is an object of the invention to provide within the combustion chamber of such an engine, substantially stable chemical means vide a beneficial material for location within a combustion chamber which, possessing the property of decreasing the tendency to carbon deposition and heat loss, enhances the efiiciency of engine op ration.

A further object of the invention is to provide a coating material for the purposes recited, among others, and which may be readily disposed within the interior of a combustion chamber and the effective properties of which will not be permanently affected by the conditions within the combustion chamber.

This application is a division of my copending application for improvements in internal combustion engines, filed July 9, 1925,

Serial No. 42,583.

At the present time the phenomenon of detonation, Jor knocking, during the operation of internal combustion engines 1s of much interest because, other conditions be- 1 ing equal, it is more pronounced with enines of high compression ratios. Accordingly this tendency to detonate with a given fuel becomes practically a limiting factor for improvement in the thermal 'efliciency 40 and power output throu h an increase in the compression ratio. is is particularly the case with the constant volume cycle type of engine which is used almost exclusively in automobiles and in aeroplanes and also to a considerable extent in small marin and stationary engines.

It is true that there are other limiting factors, such as loss in mechanical efficiency,- which may offset the gain in thermal efii- I ciency after a certain increase in the compression ratio, but the limitation due to the in'urious effects of detonation becomes operative before these other limiting factors exert their influence. In order to obviate or decrease detonation, it has been suggested that various materials be added to the fuel. t

offered for the phenomenon of detonation.

It is my view that detonation, or knocking in internal combustion engines is mainly due to a decomposition or breaking down of the unburned fuel, or in other words, to the dissociation of the larger molecules of the fuel under the influence of heat and pressure into a greater number of smaller molecules whereby there is caused a sudden rise of ressure. This rise of pressure may not be indicative of the true ressure condition within the whole body 0 the fuel-air mixture, but is rather in the nature of a localized impact. This view is supported by the following considerations; first, the'detonating tendency of various fuels is ractically a function of their thermal sta ility, for example, the tendency to detonate decreases in the following order: kerosene, ordinary gasoline, aromatic gasoline, benzol, alcohol and hydrogen, and the thermal stability in creases in the same order; second, the indicator diagram of detonating engines shows a very rapid rise of pressure which lasts only a very short period of time, is followed by an equally rapid decline, frequently occurs several times at the beginning of the expansion stroke, the peaks becoming smaller each time, and these rises of pressure are of such short duration that the corresponding pressure volume area is too small to represent an appreciable amount of useful work and hence they manifest themselves asdestructive impacts; third, detonation is accompanied by lost power, deposition of carbon and eat loss of heat to the water jacket whic loss of ower and deposition of carbon may be consldered natural results from the decomposition of the fuel, and the loss of heat to the water jacket is probably due to radiation caused by glowing particles of carbon and to the impacts; and, fourth, it has been shown that various factors which cause an increase in the rapidity of combustion and make the combustion more complete have a rather pronounced effect in counteracting detonation. This would seem to follow as an indirect result of the fact that the molecules of the fuel cannot simultaneousl undergo a reaction of combustion and of dlicomposition.

I have discovered that detonation may be counteracted directly and without accelerating combustion by tixedly disposing in the combustion chamber of a standard internal combustion engine a coating material containing a substance, or substances, which has a low melting point, or which passes into another form at a relatively low temperature. Detonation being due to a thermal decomposition of the fuel, then by brin ing the fuel-air mixture into contact with a detonation counteractant, the decomposition may be inhibited either by lowering the temperature of the unburned fuel; by catalyzing negatively the reaction of decomposition, or it may be by the prevention of a positive catalytic efi'ect on the reactionof decomposition y the walls of the combustion chamber. It may be that these effects are combined and in the present state of knowledge, it would be ver diflicult, if not impossible, to separate t emquantitatively.

lVhile it is believed that the efl'ect roduced is primarily a themal skin e ect, resulting from a cooling of the fuel-air mixture by a low melting substance or a substance which acts endothermically without melting, as, for example, the formation of an allotropic substance, it is to be considered that the efiect may be enhanced or diminished by other characteristics such as conductively, catalytic properties, reactivity, with particular reference to capability of reaction with oxygen and other com onents of the gaseous m1xture,etc. It must fiirthermore be borne in mind that such a thermal molecular skin eflect of the coating resulting in a cooling down of the unburned fuel and a counteracting of its decomposition, may also influence the rapidity of combustion, and likewise any negative catalytic effeet on the decomposition reaction may be combined with a negative catalytic effect on the combustion. However, such characteristics are probably purely accidental coincidences and are not fundamentally of concern in connection with my invention, in accordance with which detention may be counteracted by fixedly disposing within the combustion chamber of an internal combustion engine a properly adapted permanent solid substance.

It was expected and confirmed by experiments that an extreme cooling effect on the fuel-air mixture would interfere with the' functioning of the engine if not render it entirely inoperative, while the same effect. if utilized to a much smaller degree, would result in counteracting detonation without any functional interference.

In practice, the present invention comprises the utilization within a combustion chamber of a coating material containing tellurium. This low-melting metallic substance may be applied alone in a finely divided condition, as, for example, by brusl|- ing the same on a desired surface wit hin the combustion chamber, or it may be applied to the cylinder head through the use of the Schoop metal spraying process. By this latter method, the coating is caused to enter into the pores of the cylinder head where it. is surely held and not subject to substantial reaction with the constituents of the gaseous mixture. Furthermore, the coating material may comprise tellurimn admixture with a suitable binder, for example, a coating material may consist of subdivided tellurium and a silicate binder. The proportions of active substance to binder may be varied according to requirements, and it has been found that a satisfactory result is produced when a mixture containing three parts by weight of subdivided tellurium to one part by weight of a silicate is employed. Application may be accomplished by cleaning the desired surface area, coating such area with the detonation counteractant and baking or setting. This procedure may then be re eated until the desired number of as been applied. The active substance even though melted, is firmly itself, and is so incoats in the mixture, retained, does not detach timately in contact wit the binding material, and in some cases chemical combination ma actually take place, that its reactivity with the gaseous mixture is reduced to a minimum.

The amount of detonation counteractant to be applied in a particular type of engine may be readily determined by suitable tests indicatin the proper surface area to be coated in or er to obtain efiicient operation.

The detonation counteractant is fixedly disposed within the combustion chamber and its disposition is susceptible of being accomplished in a variety of ways. Its relative location within the combustion chamber may also be chosen as desired. For example, the counteractant may be applied to the top of the piston, or directly to the cylinder wall, if this wall is part of the combustion chamber, or to the cylinder head. In certain instances its exposure to the fuel-air mixture may be regulated when desired.

Utilization of the detonation counteractant on account of its endothermic properties produces a marked cooling eflcct on the fuelair mixture, so that decomposition of the unburned part is retarded i'fnot prevented. In other words, it prevents the unburned particles in the flame from reachingha temperature sufiiciently high to cause eir decomposition before actual ignition. If this effect were'to be availed of to its fullest extent, it would also prevent propagation of the flame, and accordingly proper functioning of an engine. An experiment in which a large part of the surface of a cylinder head was covered with an active su stance alone in a finely subdivided condition, illustrated the correctness of the foregoin statement in that it rendered the engine inoperative. This experiment speaks rather against an explanation by catalytic action. It is necessary therefore to apply the active substance as a coating material to only a portion of the interior of the combustion chamber or if it is desired to cover a larger area, this active substance is to be attenuated through admixture with a binder which is inert.

I have shown by a series of experiments made under actual road conditions with a special high compression Ford cylinder head which Was used on the one hand without application of a detonation counteractant and on the other, with the ap lication of a detonation counteractant t at under heavy load conditions, as for example,hill climbing, the uncoated head detonated at practically all spark and throttle positions, while with the cylinder head coated, the engine operated 3 without detonation with a wide open throttle and a fairly advanced spark. These tests were re eated and varied many times and the resu ts were concordant and satisfactory, evidencing an increase in ower output and a counteracting of the con itions to whiclndetonation is due, from which it follows that the thermal efliciency may be increased by an increase in the compression ratio without the attendant disadvantages of detonation.

The drawin is a partly sectional view exemplifying a orm of the invention wherein a permanent detonation counteractant, such as contemplated by the invention, is fixedly dis osed within the combustion chamber of an internal combustion engine in the form of a coatin applied to the exposed surfaces of the piston head and the exhaust valve, the hottest points on the walls of the chamber.

In this exemplification, a cylinder block 1, together with a high compression cylinder head 2, provides a combustion chamber 3 into which the contacts 4 of a spark plug 5 extend. A ortion of the wall of the combustion chamlier is provided by the piston head 6 on the surface of which is a coating 7 containing tellurium. Another ortion of the wall of this chamber is provi ed by the surface of an exhaust valve 8 on which there is also provided a coating 9 containing tellurium.

The detonation counteractant preferably comprises a substance or substances which are nonabrasive, and accordingly no injury to the cylinder walls will result in the event that a portion should become detached.

Among the advantages arising through the utilization of the detonation counteractant, mention may be made of the following: lack of detonation or knocking, lower fuel consumption, more flexible operation of the engine, decrease in carbon deposition, and an increase in the thermalelficiency, particularly in connection with the use of high compression engines.

It is to be understood that the invention in its broad sense is for the employment in the combustion chamber of an internal combustion engine of a material possessing the property of counteracting detonation, which material may be used alone or in admixture with a suitable binder, and to ermit the redesigning of engines having higher com: pression ratios.

While'the theory herein presented offers a basis for an understanding of the manner in which the detonation counteractant may function, and while it is supported by known facts, it is to be understood, of course, that the operativeness and racticability of the invention is not depen ent upon or limited in any way by the correctness of such theory.

Since certain changes may be made in the detonation counteractant above described and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the eneric and s ecific features of the invention l ierein described, and all statements of the scope of the invention whidh, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an internal combustion en me, the combination of a combustion cham r, and a detonation counteractant comprising tellurium and fixedly disposed within said chamber.

2. In an internal combustion engine, the combination of a combustion chamber, and a coating fixedly disposed on certain of the walls of said chamber, said coating including tellurium.

3. In an internal combustion en ine, the combination of a combustion cham er, and a coating permanently alfixed to certain of those portions of the walls of the chamber which are hottest durin engine operation, 5. In an internal combustion engine, the

said coating including to IIIIUIII. combination of a combustion chamber, and a 10 4. In an internal combustion engine, the coating fixedly disposed on certain of the combination of a combustion chamber, a walls of said chamber, said coating compris- 5 permanent detonation counteractant fixedly in an intimate admixture of sub-divided disposed Within said combustion chamber, tefiurium and a silicate. said detonation counteractant comprising In testimony whereof I affix my signature. tellurium, and a binder. EDWARD SOKAL.

which are hottest during engine operation, said coating including tellurium.

5. In an internal combustion engine, the

combination of a combustion chamber, a walls of said chamber, said coating comprispermzment detonation counteractant fixedly 111 an intimate admixture of sub-divided tell disposed within said combustion. chamber, smrl detonation counteractant comprising tellurium, and a binder.

urium and a silicate. In testimony whereof I afiix my signature.

EDWARD SOKAL.

Certificate of Correction.

rmnt No. 1,631,705. Granted June 7, 1927, w

EDWARD SOKAL.

It is hereby certified that error appears in the printed specification of the abovenumbered patent uiring correction as follows: Page 2, hue 36, for the m' word themal rea. thermal,- line 44, for conduetively read cmzdwtirvity; line 60, for the word detention read detonation; line 85, for surely read W141; and line 88, after the word tellnrinm insert the word in; and that the'said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiioe.

Signed and sealed this 19th day of July, A. D. 1927.

[emu] M. J. MOORE,

Acting Commission! of Putnam.

combination of a combustion chamber, and a i 4. In an internal combustion engine, the coating fixedly disposed on certain of the Certiflca te of Correction.

Patent No. 1,631,705. Granted June 7, 1927, to EDWARD SOKAL,

It is hereby certified that error appears in the printed specification of the abovenumbered patent re uiring correction as follows: Page 2, hne 36, for the misspelled word themal rea thermal; line 44, for conduotively read conductivity; line 60, for the word detention read detonation, line 85, for surely road swanky; and line 88, after the word tellurium insert the word in; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent ()flioa.

Signed ind sealed this 19th day of July, A. D. 1927.

[SEAL] M. J. MOORE,

Acting Cmnme'aabmr of Patents. 

